Ruby on Rails has taken the web application development world by storm. Those of us who have been writing web apps for a few years remember the good ol’ days when the leading contenders for web programming languages were PHP and Java, with Perl, Smalltalk, and even C++ as fringe choices. Either PHP or Java could get the job done, but millions of lines of legacy code attest to the difficulty of using either of those languages to deliver solid web applications that are easy to evolve. But Ruby on Rails changed all that. Now thousands of developers around the world are writing and delivering high-quality web applications on a regular basis. Lots of people are programming in Ruby. And there are plenty of books, screencasts, and tutorials for almost every aspect of bringing a Rails application into being. We say “almost every aspect” because there’s one crucial area in which Ra...